Clean install on rMBP Mid-2014, now Dell P2415Q won't turn on when restarting

[CheesePuff]

Did a clean install of the public release last night, and now my rMBP Mid-2014 model which I use on my desk in clamshell mode paired to a Dell P2415Q 4K external display no longer turns on during a reboot of the system, and if I open my MacBook only the keyboard lights come on and nothing at all on the display, forcing me to do a hard reboot and then wait for the MacBook display to turn on then I can close it again.

Never happened on El Capitan... anyone else seeing this and know of a fix?

 

[CheesePuff]

Anyone else happen to be on Sierra now with a MacBook Pro and the Dell P2415Q or P2715Q monitors?

 

[reasonrulaz]

Yes, i experienced exactly same issue with Samsung 4k monitor.

It's known issue with MacOs 10.12.. I'm waiting 10.12.1 for solution.

 

[CheesePuff]

Yes, i experienced exactly same issue with Samsung 4k monitor.

It's known issue with MacOs 10.12.. I'm waiting 10.12.1 for solution.

Don't hold your breath, on beta 4 now and same issue.

 

[quidire]

Did 10.12.1 solve this problem? I was thinking of getting a P2415Q for use as a vertical complement to my 27" iMac…

 

[BenTrovato]

Did 10.12.1 solve this problem? I was thinking of getting a P2415Q for use as a vertical complement to my 27" iMac…

It works fine on 13" MBP and 2012 Mac mini. I noticed it was so slow responding coming out of sleep with sierra but it is better on 10.12.1

 

[CheesePuff]

Did 10.12.1 solve this problem? I was thinking of getting a P2415Q for use as a vertical complement to my 27" iMac…

I don't think you will have an issue with it connected to an iMac - my issue is when operating a rMBP 15" in clamshell (closed) mode.

 

[CheesePuff]

10.12.2 Public Beta 1 fixed this issue!